3D Vision

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Creating Directory for new robot into LabView Hololens app


I am new to LabVIEW and this new exciting technique and I was wondering if someone could help explain or provide a step by step tutorial of how one can successfully take an OBJ model can create the proper directory structure for a given robot?


below is a link provided by an national Instrument associate and it provides a detailed tutorial of how to convert a CAD model into a OBJ and begins to elaborate on the need to create a directory structure but does not give great details as to how it should be done. Can someone please clearify this and help me create a correct directory structure for a given robot and how to involve it in to LabVIEW as instructed in the forum linked below??




kind regards

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Re: Creating Directory for new robot into LabView Hololens app

You'll find below additional detailed information about the use of directories to build a robot as explained in the document you refer to. Hopefully, it will help you.


In any case, I think that the most difficult step is to transform the robot CAD models into the various .obj files corresponding to each axis. If you give me a link where I can find your robot CAD model, or if you post it in this forum, I can take a stab at it and post the files and directory structure back in this forum.


Robot Directory

Overall, I think that the directory structure is simple. You have one directory for the robot. That directory contains one directory per axis. The alphabetical order of the axis directories represents the order on which the axes are mounted on each order (this is the reason why the rail, carrier, and base directories are called "aaarail", "aacarrier", "abase" because the base is mounted on the carrier that is mounted on the rail in the document you referred to).

In addition, you should have in the robot directory two text files: moves.txt and offsets.txt. These two files contain the information required to move the axes.


Moves text file.

The moves.txt file contains the type of movement of each robot axis and the movement orientation (rotation axis or translation direction) of the robot axes in the original position of all robot axes. There should be one line per axis. This format assumes that all axes rotate around or translate in one of the main directions of the coordinate system of the robot CAD model (X, Y, Z). Each type of movement is given by Trans for translation or Rot for rotation followed by the coordinate direction (X, Y, or Z). If the axis does not move (like the rail or base in the referred document, the info should be "None").


Offsets Text File.

The other text files, offsets.txt, provides the information about the position of each axis relative to each other. There should be one line per axis. Each line consist of three values separated by a tab character. The values for one axis are the X, Y, and Z values of the offset position of the rotation axis of the current axis relative to the axis on which it is mounted. This information is necessary only if the axis rotates. If the current axis translates or does not move ("None"), then you can put 0, 0, 0 for that axis (but you still need to have a line for that axis in the offsets.txt file). The offset information is generally provided by robot manufacturers.


Material files

The last type of files you might find in the robot directory are the .mtl files. Those files define the appearance of the mesh as displayed in 3D. You can put the .mtl files each each axis directory if you prefer but it is easier to maintain and modify a uniform look among the different parts of the robot if all the .obj files refer to the same appearance .mtl files from the various axis directories.


Axis Directories

For the axis directories, each directory should contain all the .obj files of the meshes that move with that axis. There could be only one .obj file in any given axis directory. The .obj file format uses .mtl files for the appearance. You can have the .mtl file in the same directory than the .obj file or you can have the .mtl file in the the top robot directory so that all .obj files in the various axis directories use all the same .mtl files.


Let me know if you have any specific question about anything mentioned above. 

Marc Dubois
HaroTek LLC


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